Researchers at Kyoto University have discovered a way to create fully functioning sperm from embryonic stem cells that were harvested from mice. Not only that but they then turned around and fertilized mouse eggs in the laboratory that were then implanted as embryos into surrogate mouse mothers.
Apparently this is something that scientists have been trying to do for years with the hope that the technology could be upscaled to work with human beings suffering from infertility. Until this discovery though all attempts have failed to produce viable offspring.
Since 2009, the team from Kyoto University has been working on this problem, and devised a special method for making the cells viable.
The researchers needed a way to coax early embryo cells, called epiblasts, into what are known as primordial germ cells (the cellular precursor to sperm and eggs). The technique they developed used induced signaling of the protein BMP4, which is known to play an active role in the creation of germ cells. For the current research, the scientists made epiblast-like cells using embryonic stem cells, growth factors, and proteins that help the cells grow. Then, they put their BMP4-based method to work to turn the epiblasts into primordial germ cells.
The germ cells were injected into the testes of sterile mice. After some time, the testes were removed, and the researchers found mature sperm. The sperm was collected and used to fertilize mice eggs in vitro. The eggs were then implanted into female mice. The experiment resulted in the birth of 65 healthy mouse babies, where the mice were sexually viable and capable of having their own children.
As an interesting side note, which my wife pointed out when I told her about this, wouldn’t this be similar to cloning?